Molecular Characterization and Antimicrobial Profiling of Escherichia coli isolates from Indian Camelus

Background: Escherichia coli is frequently associated with multiple antimicrobial resistances and a major cause of bacterial extraintestinal infections in livestock and humans. Escherichia coli resides in the lower digestive tract as harmless commensals but a subset of E. coli strains has acquired the ability due to acquisition of virulence and antibiotic genes, cause intestinal or extraintestinal diseases. Methods: In this field-laboratory investigation during 2020-2021, samples were taken from different localities of Bikaner district and surrounding are of Rajasthan. A total no. of 70 fecal samples were collected and immediately transferred to the Department of Veterinary Microbiology. In the laboratory, the collected samples were further processed for isolation and identification of E. coli bacteria. Result: Confirmation of E. coli was done using primary and biochemical test which are screened for hemolysin property, biofilm formation, antibiogram study and antibiotic resistance gene. All the isolates of E. coli used to show characteristic metallic sheen on EMB agar plate and excellent identification was done with VITEK 2 system. All the camel isolates shown partial hemolysis on sheep blood agarand 45.71% camel isolates were positive for biofilm formation. All these 70 E. coli isolates from camel were resistant to Penicillin (94.38%) which was followed by amoxicillin+sulbactam (85.71%), erythromycin (71.14%), cefixime+clavulanic acid (71.43%). Highest sensitivity to chloramphenicol (81.28%) followed by sulphadiazine (48.57%) and cotrimoxazole (48.28%). All these 70 isolates were screened for antibiotic resistance genes. On the basis of molecular screening of the antibiotic resistance genes, majority of the isolates carried BlaTEM gene in camel (56/70; 80%), followed by StrA (29/70; 41.40%), Sul-3 in (22/70; 31.42%), Sul-2 (18/70; 25.71%), aadA (28/70; 40%), tet(B) (22/70; 31.42%) isolates.